INVITATION PAPER: C.P. Alexander Fund: HOST CHOICE BY APHIDIID PARASITOIDS (HYMENOPTERA: APHIDIIDAE): HOST RECOGNITION, HOST QUALITY, AND HOST VALUE

1996 ◽  
Vol 128 (6) ◽  
pp. 959-980 ◽  
Author(s):  
M. Mackauer ◽  
J.P. Michaud ◽  
W. Völkl
Keyword(s):  
Host Choice ◽  
Growth Potential ◽  
Physical Contact ◽  
Response Threshold ◽  
Host Recognition ◽  
Egg Load ◽  
Host Quality ◽  
State Variables ◽  
Female Progeny ◽  
Potential Host

AbstractSpecies in the family Aphidiidae (Hymenoptera) parasitize exclusively ovoviviparous aphids. Females use a variety of information to detect and evaluate suitable hosts. Olfactory cues associated with aphids, or the aphids’ host plant, are important for host location. Visual cues including aphid colour, shape, and movement can be evaluated from a distance without physical contact; aphid movement may act as a releasing stimulus for attack. Contact chemosensory cues (gustatory cues) are evaluated by antennation of the host cuticle and during ovipositor probing. A potential host must conform to the wasp’s response profile and satisfy minimum physiological and dietary requirements for immature development and growth. Host quality is determined in part by attributes specific to each aphid species and in part by each aphid’s individual-specific growth potential. Host quality for male and female progeny may vary as a result of different patterns of resource allocation and sexual size dimorphism. For an encountered aphid to be accepted as a host, its perceived value must exceed the wasp’s response threshold for oviposition. Host value, as opposed to host quality, varies dynamically with parasitoid state variables such as age, egg load, and prior experience. A conceptual model of host choice by aphidiid wasps is presented.

The influence of host quality on progeny and sex allocation in the pupal ectoparasitoid,Muscidifurax raptorellus(Hymenoptera: Pteromalidae)

1998 ◽  
Vol 88 (3) ◽  
pp. 299-304 ◽  
Author(s):  
J.A. Harvey ◽  
G.J.Z. Gols
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Adult Development ◽  
Development Time ◽  
Host Quality ◽  
Adult Size ◽  
Female Progeny ◽  
Interspecific Differences ◽  
Adult Parasitoid ◽  
Secondary Sex Ratio

AbstractMuscidifurax raptorellusKogan & Legner is a gregarious pteromalid ectoparasitoid that attacks pupae and pharate adults from several families of the higher Diptera. Egg-to-adult development time, adult parasitoid size and emerging offspring ( = secondary) sex ratio ofM. raptorelluswere compared with clutch size in two hosts that differed greatly in mass, the smallMusca domesticaLinnaeus and the largerCalliphora vomitoriaLinnaeus. The mean number of emerging parasitoids did not vary significantly with host species, although slightly higher clutch sizes were recorded inC. vomitoria. Irrespective of offspring sex, parasitoids completed development more rapidly inM. domesticathan inC. vomitoria. In the small host, the development time and adult size ofM. raptorelluswere negatively correlated with clutch size. By contrast, female parasitoid size was unaffected by clutch size in the larger host,C. vomitoria. In both hosts, female parasitoids were significantly larger than male parasitoids. The secondary sex ratio (percentage males) of emerging parasitoids was significantly lower inC. vomitoria, and varied with clutch size in both hosts. InC. vomitoria, the greatest proportion of females emerged from hosts with the highest clutch sizes, whereas inM. domesticahosts with the highest clutch sizes produced the lowest proportion of female progeny. The results described here show that the development ofM. raptorellusis profoundly affected by interspecific differences in host quality. Our results suggest that mating structure and host quality have potentially different effects on sex ratio decisions inM. raptorellus, and perhaps other gregarious parasitoids.

scholarly journals Regulators of nitric oxide signaling triggered by host perception in a plant pathogen

2020 ◽  
Vol 117 (20) ◽  
pp. 11147-11157 ◽  
Author(s):  
Yi Ding ◽  
Donald M. Gardiner ◽  
Di Xiao ◽  
Kemal Kazan
Keyword(s):  
Nitric Oxide ◽  
Specific Binding ◽  
Physical Contact ◽  
Plant Roots ◽  
Host Recognition ◽  
No Production ◽  
Soil Pathogens ◽  
Nitric Oxide Signaling ◽  
Molecular Events ◽  
Host Signals

The rhizosphere interaction between plant roots or pathogenic microbes is initiated by mutual exchange of signals. However, how soil pathogens sense host signals is largely unknown. Here, we studied early molecular events associated with host recognition in Fusarium graminearum, an economically important fungal pathogen that can infect both roots and heads of cereal crops. We found that host sensing prior to physical contact with plant roots radically alters the transcriptome and triggers nitric oxide (NO) production in F. graminearum. We identified an ankyrin-repeat domain containing protein (FgANK1) required for host-mediated NO production and virulence in F. graminearum. In the absence of host plant, FgANK1 resides in the cytoplasm. In response to host signals, FgANK1 translocates to the nucleus and interacts with a zinc finger transcription factor (FgZC1), also required for specific binding to the nitrate reductase (NR) promoter, NO production, and virulence in F. graminearum. Our results reveal mechanistic insights into host-recognition strategies employed by soil pathogens.

scholarly journals Novel regulators of nitric oxide signaling triggered by host perception in a plant pathogen

2019 ◽  
Author(s):  
Yi Ding ◽  
Donald M. Gardiner ◽  
Di Xiao ◽  
Kemal Kazan
Keyword(s):  
Nitric Oxide ◽  
Physical Contact ◽  
Plant Roots ◽  
Host Recognition ◽  
No Production ◽  
Soil Pathogens ◽  
Nitric Oxide Signaling ◽  
Molecular Events ◽  
Repeat Domain ◽  
Host Signals

AbstractThe rhizosphere interaction between plant roots or pathogenic microbes is initiated by mutual exchange of signals. However, how soil pathogens sense host signals is largely unknown. Here, we studied early molecular events associated with host recognition in Fusarium graminearum, an economically important fungal pathogen that can infect both roots and heads of cereal crops. We found that host-sensing prior to physical contact with plant roots radically alters the transcriptome and triggers nitric oxide (NO) production in F. graminearum. We identified an ankyrin-repeat domain containing protein (FgANK1) required for host-mediated NO production and virulence in F. graminearum. In the absence of host plant, FgANK1 resides in the cytoplasm. In response to host signals, FgANK1 translocates to the nucleus and interacts with a zinc finger transcription factor (FgZC1), also required for NO production and virulence in F. graminearum. Our results reveal new mechanistic insights into host-recognition strategies employed by soil pathogens.

scholarly journals Potential Host Range of the Larval Endoparasitoid Cotesia vestalis (=plutellae) (Hymenoptera: Braconidae)

2017 ◽  
Vol 9 ◽  
pp. 117954331771562 ◽  
Author(s):  
Satoshi Hiroyoshi ◽  
Jeffrey A Harvey ◽  
Yutaka Nakamatsu ◽  
Hisashi Nemoto ◽  
Jun Mitsuhashi ◽  
...  
Keyword(s):  
Host Range ◽  
Host Species ◽  
Diamondback Moth ◽  
Growth Potential ◽  
Parasitoid Wasps ◽  
Cotesia Vestalis ◽  
Potential Host ◽  
First Instar ◽  
Developmental Capacity ◽  
Lepidopteran Host

Many parasitoid wasps are highly specialized in nature, attacking only one or a few species of hosts. Host range is often determined by a range of biological and ecological characteristics of the host including diet, growth potential, immunity, and phylogeny. The solitary koinobiont endoparasitoid wasp, Cotesia vestalis, mainly parasitizes diamondback moth (DBM) larvae in the field, although it has been reported that to possess a relatively wide lepidopteran host range. To better understand the biology of C vestalis as a potential biological control of hosts other than the DBM, it is necessary to determine suitability for potential hosts. In this study, the potential host range of the wasp and its developmental capacity in each host larva were examined under laboratory conditions using 27 lepidopteran species from 10 families. The wasp was able to parasitize 15 of the 27 species successfully. Some host species were not able to exclude C vestalis via their internal physiological defenses. When parasitization was unsuccessful, most hosts killed the parasitoid at the egg stage or early first-instar stage using encapsulation, but some host species disturbed the development of the parasitoid at various stages. No phylogenetic relationships were found among suitable and unsuitable hosts, revealing that host range in some endoparasitoids is not constrained by relatedness among hosts based on immunity.

Host recognition and acceptance behaviour in two aphid parasitoid species: Aphidius ervi and Aphidius microlophii (Hymenoptera: Braconidae)

1994 ◽  
Vol 84 (1) ◽  
pp. 57-64 ◽  
Author(s):  
F. Pennacchio ◽  
M.C. Digilio ◽  
E. Tremblay ◽  
A. Tranfaglia
Keyword(s):  
Acyrthosiphon Pisum ◽  
Selection Process ◽  
Host Choice ◽  
Aphid Species ◽  
Host Recognition ◽  
Aphidius Ervi ◽  
Aphid Parasitoid ◽  
Host Aphid ◽  
Close Range

AbstractThe host preference and acceptance behaviour of populations of Aphidius ervi Haliday and A. microlophii Pennacchio & Tremblay from southern Italy was investigated. In no host-choice conditions, A. ervi females showed significantly higher attack and oviposition rates on the natural host Acyrthosiphon pisum (Harris) than on the non-host aphid Microlophium carnosum (Buckton)(Homoptera: Aphididae). In contrast, A. microlophii, which specifically parasitizes M. carnosum in the field, attacked both aphid species. However, dissections showed that oviposition of A. microlophii occurred only in a few of the attacked Acyrthosiphon pisum and was significantly less frequent than in M. carnosum. These results were confirmed in experimental host-choice conditions, suggesting that Aphidius microlophii oviposition is possibly regulated by a host haemolymphatic kairomone. Hybrids obtained by crossing A. ervi females with A. microlophii males attacked and oviposited in both aphid species, suggesting that these behavioural events have a strong genetic basis. The oviposition into host or non-host aphids did not elicit an immune defence reaction. The presence of the host's food-plant had no evident close-range effects on parasitoid attack and oviposition in non-host aphids. Aphidius microlophii reared on the non-host aphid Acyrthosiphon pisum produced a significant higher number of mummies after a few generations, suggesting a possible role of larval and early adult conditioning in the host selection process. These results, together with those from previous studies, suggest that Aphidius ervi is best considered as a complex of differentiated populations, characterized by a varying degree of genetic divergence.

Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

1976 ◽  
Vol 34 ◽  
pp. 130-131
Author(s):  
V.K. Berry
Keyword(s):  
Oxidation Reaction ◽  
Electron Microscope Study ◽  
Elemental Sulfur ◽  
Thiobacillus Ferrooxidans ◽  
Physical Contact ◽  
Metal Sulfides ◽  
Low Grade ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

The Solidarity of Distance1

2005 ◽  
Vol 36 (3) ◽  
pp. 103-115 ◽  
Author(s):  
Robert A. Wicklund
Keyword(s):  
Physical Contact ◽  
Emotional Distance ◽  
Starting Point ◽  
Shared Emotions ◽  
Common Goals ◽  
Full Interaction ◽  
The Individual ◽  
Social Incompetence

Abstract: Solidarity in the classic sense pertains to a cohesion among humans that entails physical contact, shared emotions, and common goals or projects. Characteristic cases are to be found among families, close friends, or co-workers. The present paper, in contrast, treats a phenomenon of the solidarity of distance, a solidarity based in fear of certain others and in incompetence to interact with them. The starting point for this analysis is the person who is motivated to interact with others who are unfamiliar or fear-provoking. Given that the fear and momentary social incompetence do not allow a full interaction to ensue, the individual will move toward solidarity with those others on a symbolic level. In this manner the motivation to approach the others is acted upon while physical and emotional distance is retained.

Sign in / Sign up

Export Citation Format

Share Document